Project Summary Over 1 million US older adults each year require nursing home care after acute hospitalization. While a short-term stay is a common goal, many patients fail to recover and require long-term placement. Delirium, an acute change in brain-functioning that can lead to permanent cognitive impairment, is an important, preventable condition that may prevent full recovery and lead to long- term placement in nursing homes. The objectives of this study are to describe the current landscape of delirium in the nursing home setting using valid and federally-mandated delirium assessment tools. A unique aspect of this study is to examine the extent delirium may lead to an inappropriate diagnosis of Alzheimer's disease and psychoactive prescribing. To complete these objectives, this research project will analyze a nationwide and contemporary dataset of nursing home resident care plans linked to Medicare program data and prescription dispensing data. The project will be able to uniquely inform the Medicare program, policymakers, clinicians and patients/families about the experience of delirium in nursing home setting.